Masses of small bodies [Elektronische Ressource] : mass estimation of small solar system bodies using radio science data from close flybys / vorgelegt von Thomas Paul Andert

Masses of Small Bodies:Mass estimation of small solar system bodiesusing Radio Science data from close flybysI n a u g u r a l – D i s s e r t a t i o nzurErlangung des Doktorgrades¨der Mathematisch–Naturwissenschaftlichen Fakultat¨ ¨der Universitat zu Kolnvorgelegt vonThomas Paul Andertaus Lichtenfels¨Koln, Januar 2010Berichterstatter: P. D. Dr. M. Pa¨tzoldProf. Dr. J. SaurProf. Dr. B. Ha¨uslerTag der mu¨ndlichen Pru¨fung: 12.01.2010iAbstractThe Radio Science technique enables to estimate the mass and other gravitationalparameters of a solar system body from spacecraft observations very precisely. It usesthe radio link between ground station and spacecraft. The frequency shift of the radiosignal is proportional to the relative velocity change between spacecraft and groundstation. If a spacecraft performs a close flyby at a solar system body, the velocityof the spacecraft is changed by the gravitational attraction of the body. If all othercontributions on the radio signal are known, the remaining frequency change is solelyduetothegravitationalattraction. Aleastsquarefitcanbeperformedonthefrequencyresiduals to derive from it gravitational parameters.Within this thesis models were developed and merged into a software package withwhich it is possible to determine the orbit of a spacecraft precisely and to predictaccurately the frequency to be observed at a ground station.